There are so many different side characters who only have two lines, but each of them were cast with care and feel like real people who are living through their day and intersecting with John McLane. I love this movie for it.
https://www.youtube.com/watch?v=8RVVJmuoAQ4
On the other hand, I just watched Michael Bay's Ambulance, which is a prolonged police chase through downtown Los Angeles and the only people who seem to be on the street are criminals and dozens of police cars. At no point are we in touch with anyone who isn't directly contributing to the story. The reality is that downtown LA is packed full of traffic and the story would have taken a very different (and interesting) angle if it reckoned with the fact that getting through the traffic is it's own game.
Die Hard With a Vengeance, however, acknowledges this reality and comes up with some very creative scenarios for our protagonists to overcome, and it makes for a far more compelling movie as a result. It feels far more realistic, even in a movie as heightened as this.